So he was right, someone else suggested this theory the other day. The byte it patches is 0x180 in each 8K bank. The value on the ROM is 0x60, it replaces it with 0x05.

Why is it that copynes wouldn't read it as the patched value? Doesn't it see it just as the NES would?

I'd be very suprised if it didn't read the patched value... HOWEVER, the chip also watches 6000-7FFFh. So viewing the ROM might shed some clues on it. They hooked up WRAM /CE to the chip also, so maybe some accesses to 6000-7FFFh trigger the "fix". This way, the ROM gets patched after it executes code /loads data once maybe. Just a guess.

That could be, worth a shot anyways. The data dumped using normal sxrom plugin actually does not boot. It also may be patching more than that one address, I figured the value is supposed to be 0x05 because the code nearby suggests that's what it should be and changing it to this allows the game to seemingly run fine.

On a side note, why the heck would they go thru this trouble to fix a bad ROM run? Wouldn't it be more cost effective just too run a new batch, rather than create a specialized PCB and throwing in the patch chip?

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